The companies argued the court should affirm Superior Court Judge Peter Michalski's 1999 ruling throwing out the suit. There isn't enough evidence for a jury to conclude there was a conspiracy, they said.

A decision isn't expected for months or years.

''You have to look at the panorama of all the evidence in the case,'' said Parker C. Folse, a lawyer for the plaintiffs. ''We think that Judge Michalski looked at each piece of evidence individually.''

Lawyers for the fishermen argue that the judge took on the jury's function by resolving issues of fact that were in sharp dispute. They say that while much of the evidence was circumstantial, there was also direct evidence of conspiracy.

Defense attorneys said Judge Michalski found no evidence of conspiracy, and applied the correct legal standard in issuing summary judgments for the importers and processors.

''Price exchanges in an open market are lawful,'' said Douglas Fryer, a lawyer for the processors. Plaintiffs didn't provide evidence of meetings between the alleged conspirators, the lawyers said.

Folse, the fishermen's lawyer, said prices paid to fishermen dropped severely while consumer prices in Japan remained stable or even rose. But the processors argued there was no proof of any agreement involving all defendants taking specific steps collectively to depress or fix prices.

Fishermen's attorneys filed the suit in 1995, seeking $500 million in actual damages and $1 billion in punitive damages. Both sides spent millions of dollars preparing the case before Michalski issued the summary judgments. Thirty-four minor defendants settled out of court for about $11 million, but the major companies fought the suit.